Unmanned aircraft are frequently used for reconnaissance flights over hazardous areas. These unmanned aircraft are radio-controlled. Helicopters are particularly practical for taking reconnaissance photographs because they are able to hover in a practically stationary position and have vertical take-off and vertical landing capabilities.
Conventional unmanned helicopters comprise a main body that accommodates the internal combustion engine and essentially consists of a covered three-dimensional framework. The manufacture of such a design is relatively costly and also results in a heavy construction that may reduce the maximum payload.